code: def test_maximum_sharpe_ratio():
      d = d_pass[4]
      pf = build_portfolio(**d)
      max_sharpe_weights = np.array(
          [
              0.0,
              0.41322217986076903,
              0.5867778201392311,
              2.2858514942065993e-17,
          ]
      )
      ef_opt_weights = pf.ef_maximum_sharpe_ratio()
      assert np.allclose(
          ef_opt_weights.values.transpose(),
          max_sharpe_weights,
          atol=weak_abse,
      )
  
imports: import datetime
  import os
  import pathlib
  import matplotlib.pylab
  import numpy
  import pandas
  import pytest
  import quandl
  import yfinance
  from finquant.efficient_frontier import EfficientFrontier
  from finquant.portfolio import Portfolio, build_portfolio
  from finquant.stock import Stock
label_desc: Use image node_id 11 for calling a global function with example usage: test_maximum_sharpe_ratio() without return types